Performance of the CMS electromagnetic calorimeter in the LHC Run II

Abstract Many physics analyses using the CMS detector require accurate, high resolution electron and photon energy measurements. The increase of instantaneous luminosity and of the number of concurrent p–p collisions (pileup) makes precise energy reconstruction more challenging. Presented are the performance of the CMS ECAL during LHC Run II, as well as the calibration and monitoring strategies to keep these effects to the minimum.